Violent turf battles between the cartels are being waged on our streets. Some say what's happening is a threat to national security.

While the streets of our city are a long way from the bloodshed and violence associated with the drug cartels along the U.S.-Mexico border, Houston has become home to some of these ultra-dangerous, highly-sophisticated criminal gangs.

"They are a major supplier of drugs that go through Houston," said Chief Harold Hurtt of the Houston Police Department.

The Drug Enforcement Administration (DEA) estimates that 92% of the illegal drugs that come into the U.S. cross the southwestern border. Almost everything from Mexico comes through Houston, in part because of our geography. We have the dubious distinction of being one of the major drug distribution points for the Gulf Cartel and it's become a multi-billion dollar a year business.

"We see marijuana coming into Houston, cocaine, heroin, and methamphetamine," said Associate SPC Agent Thomas Hinojosa of the DEA.

The majority of which is then sold and dispersed to dealers in other parts of the country. Who's selling the drugs? Try hundreds, if not thousands, of local cartel operatives who are greedy and hungry for money.

"Once you enter that underworld, then you see everybody that's doing it. You'd be surprised," said Jose who used to import and sell marijuana and cocaine for the Gulf Cartel until he was arrested in a sting operation.

Jose asked us to keep his identity a secret. He said doing the cartel's dirty work is a cutthroat business.

"You always know that at some point either you are going to be arrested or you may wind up dead," said Jose.

As an elite member of the cartel, Jose said his greatest fear wasn't the authorities, but the threat of violence from his rivals, many of whom are dealers working for same cartel. He said, in a business based on gluttony and power, there's no such thing as loyalty.

"It could be anybody, another cartel, it could be your best friend," said Jose. "If somebody finds out that you have a large quantity that's accessible to you, then they'll try to kidnap you or kill you. Maybe even kidnap one of your family members."

While there's no hard statistics to back those claims, law enforcement, whether it's local, state or federal, are able to make that connection between the violence on our streets and the cartels as they dig deeper in a criminal investigation.

"As a whole, we are doing a good job of indentifying cells in this region and attacking them from within and taking them out," said Hinojosa.

In the last 13 months, federal, state, and local authorities have seized more than 14,000 pounds of illegal drugs in the Houston area. That's nearly a thousand pounds a month with a street value of nearly $22 million.

The bus lines that bring people in from Mexico to Houston are being used by these criminal gangs to smuggle drugs into the country. The DEA seized hundreds of kilos of cocaine during a bust three years ago. All but one of people involved in the operation have been convicted.

"There is such a market that you can't stop it from coming in because there's so much money involved at the same time," said Jose.

It's a war being fought on both sides of the border that's far from being won.